1) Field of the Invention
The present invention relates to network management in general and in particular to devices which indicate the bandwidth usage in communications networks.
2) Prior Art
The use of LANs for interconnecting data terminal equipment (DTE) is well-known in the prior art. A conventional LAN includes a transmission medium (wire, fiber, etc.) to which a plurality of DTEs are connected. The exchange of information between DTEs are controlled by architectures and protocols associated with the particular AN.
The popularity and use of LANs as an information distribution system have been increasing and will continue to increase. As a result, several steps have been taken to improve the reliability of the LAN. One major step is the standardization of architectures and protocols used in the LAN. The IEEE Project 802 Local Network Standards provides architectures and protocols for three types of LANs, namely; ETHERNET IEEE (802.3), Token Bus (IEEE 802.4) and Token Ring (IEEE 802.5). By standardizing the LANs, different manufacturers' equipment can communicate without the need of one manufacturer having detailed knowledge of the structure and/or operation of another manufacturer's equipment.
In addition to standardizing the network, several tools are required to measure various network functions and provide data which is used by a management station to control and optimize the operation of the network. Among the many tools is one which shows the utilization of the network at a given time. IBM Technical Disclosure Bulletin, Vol. 29, No. 12, May 1987 (pgs. 5419-5422) describes an apparatus and a technique for measuring utilization in a Token Ring Network. The apparatus includes an adapter with a modified front end chip (MFEC) and associated circuitry for calculating the ring utilization from the mathematical expression: EQU Ring Utilization (RU)=1-Ring latency/Available Average Token Rate
where ring latency is the time between two consecutive free tokens and available average token rate is the time between free tokens. As will be explained below, a free token gives a station or DTE the right to transmit information on the network. A likely drawback with this system is that it is costly and it cannot be easily integrated into existing adapter hardware. This is so because the MFEC calls for a toroid (passive inductive connection) interfacing the adapter to the ring transmission media. The configuration is such that the ring transmission media passes through the toroid.
U.S. Pat. No. 4,943,979 describes a star controller for attaching to a bus network and to regenerate messages from the bus to multiple ports. The star controller includes a message relay logic which can be used to measure network bandwidth utilization by sampling the operating state of the message relay logic. The value of a counter can be read by message exchanges over a management link and software can determine the percentage of utilization from the count and from knowledge of sampling interval and rate. Among the deficiencies of this patent is the lack of detailed teaching to enable an artisan to implement the bandwidth measurement. In addition, the teachings may be applicable only to a bus type network.